Digital processing of images is well known in the art, as exemplified by U.S. Pat. Nos. 4,674,125; 4,797,942 and 5,335,328. For example, it is well known to filter, re-size, project and warp images (see Wolberg, G. "Digital Image Warping", IEEE Computer Society Press 1988; Lim, J. S. "Two-dimensional Signal and image Processing", Prentice Hall 1990; and Elliot, D. F. "Handbook of Digital Signal Processing" Academic Press, 1987). The use of these and other prior art imaging effects is characterized by image continuity problems arising at the boundaries of the images (e.g. top/bottom, left/right). These problems are particularly acute during digital filtering due to the discontinuities at the image edges.
One solution to these problems involves mirroring the half kernel of a filter for moderating the effect of boundary conditions on processing of the image. Digital filters which are adapted to perform this function are typically implemented in integrated circuits. However, maximum clock rate and the sizes of elements used to provide line delays, etc., impose restrictions on the sizes of the images that such integrated circuits are capable of processing within a given time frame. The frame rate and the number of pixels per frame determines the number pixels per second that must be processed to maintain full frame processing. Thus, the maximum clock speed of an integrated circuit places a limitation on the maximum number of pixels that can be processed per second by a single integrated circuit. Software implementations of such digital filters are limited by the maximum throughput of the controlling CPU.
Accordingly, it would be desirable in a digital signal processing system to provide full frame processing of images with the digital filter function spread over a plurality of integrated circuit chips operating in parallel, and each operating at a high clock rate for maximizing the number of pixels processed per second per chip.
However, in order to realize such a digital signal processing system, the image must be extended seamlessly between respective ones of the parallel-operating digital filters, which is a feature currently unavailable in the prior art.